Automatic systems, such as vehicle transmissions, and fuel injection systems generally include a number of solenoids that are actuated to control those systems. In the case of a vehicle transmission, a driver circuit actuates solenoids to engage and disengage hydraulically controlled clutches. By selectively engaging different clutches or combinations of clutches within the automotive transmission, a transmission control system may select a gear ratio for the transmission. In the case of a fuel injection system, a driver circuit may actuate solenoids that control fuel injectors. The fuel injectors release fuel into the cylinders of the engine.